Distributed process control systems, like those used in chemical, petroleum or other process plants, typically include one or more process controllers communicatively coupled to one or more field devices via analog, digital or combined analog/digital buses, or via a wireless communication link or network. The field devices, which may be, for example, valves, valve positioners, switches and transmitters (e.g., temperature, pressure, level and flow rate sensors), are located within the process environment and generally perform physical or process control functions such as opening or closing valves, measuring process parameters, etc. to control one or more process executing within the process plant or system. Smart field devices, such as the field devices conforming to the well-known Fieldbus protocol, may also perform control calculations, alarming functions, and other control functions commonly implemented within the controller. The process controllers, which are also typically located within the plant environment, receive signals indicative of process measurements made by the field devices and/or other information pertaining to the field devices and execute a controller application that runs, for example, different control modules which make process control decisions, generate control signals based on the received information and coordinate with the control modules or blocks being performed in the field devices, such as HART®, WirelessHART®, and FOUNDATION® Fieldbus field devices. The control modules in the controller send the control signals over the communication lines or links to the field devices to thereby control the operation of at least a portion of the process plant or system.
Information from the field devices and the controller is usually made available over a data highway to one or more other hardware devices, such as operator workstations, personal computers or computing devices, data historians, report generators, centralized databases, or other centralized administrative computing devices that may be placed in control rooms or other locations away from the harsher plant environment. In some process plants, at least some of these hardware devices are centralized across the process plant or across a portion of the process plant. These hardware devices run applications that may, for example, enable an operator to perform functions with respect to controlling a process and/or operating the process plant, such as changing settings of the process control routine, modifying the operation of the control modules within the controllers or the field devices, viewing the current state of the process, viewing alarms generated by field devices and controllers, simulating the operation of the process for the purpose of training personnel or testing the process control software, keeping and updating a configuration database, etc. The data highway utilized by the hardware devices, controllers and field devices may include a wired communication path, a wireless communication path, or a combination of wired and wireless communication paths. In some process plants, at least a portion of the data highway includes a process control network that supports big data.
As an example, the DeltaV™ control system, sold by Emerson Process Management, includes multiple applications stored within and executed by different devices located at diverse places within a process plant. A configuration application, which resides in one or more workstations or computing devices, enables users to create or change process control modules and download these process control modules via a data highway to dedicated distributed controllers. Typically, these control modules are made up of communicatively interconnected function blocks, which are objects in an object oriented programming protocol that perform functions within the control scheme based on inputs thereto and that provide outputs to other function blocks within the control scheme. The configuration application may also allow a configuration designer to create or change operator interfaces which are used by a viewing application to display data to an operator and to enable the operator to change settings, such as set points, within the process control routines. Each dedicated controller and, in some cases, one or more field devices, stores and executes a respective controller or field device application that runs the control modules assigned and downloaded thereto to implement actual process control functionality. The viewing applications, which may be executed on one or more operator workstations (or on one or more remote computing devices in communicative connection with the operator workstations and the data highway), receive data from the controller or field device application via the data highway and display this data to process control system designers, operators, or users using the user interfaces, and may provide any of a number of different views, such as an operator's view, an engineer's view, a technician's view, etc. A data historian application is typically stored in and executed by a data historian device that collects and stores some or all of the data provided across the data highway while a configuration database application may run in a still further computer attached to the data highway to store the current process control routine configuration and data associated therewith. Alternatively, the configuration database may be located in the same workstation as the configuration application.
In some arrangements, a distributed process control system includes a big data network or system that provides an infrastructure for supporting large scale data mining and data analytics of process data (referred to herein interchangeably as a “process control big data network” or a “big data process control network.” Examples of such process control system big data networks or systems may be found in aforementioned U.S. patent application Ser. No. 13/784,041 entitled “BIG DATA IN PROCESS CONTROL SYSTEMS,” and in aforementioned U.S. patent application Ser. No. 14/212,493 entitled “DISTRIBUTED BIG DATA IN A PROCESS CONTROL SYSTEM.” A big data process control network or system includes a plurality of nodes to collect and store all (or almost all) data that is generated, received, and/or observed by devices included in and associated with the process control system or plant. The nodes may be interconnected via a big data network backbone, e.g., an Internet Protocol backbone, a backbone utilizing a process control-specific protocol that supports big data, or other networked set of computing devices. In some embodiments, the backbone of the big data network may intersect at least partially with at least part of the process control system that does not support big data.
In some process plants that support big data, one of the nodes of the process control big data network is a process control system big data apparatus at which big data is centrally stored, managed, and/or historized. The process control system big data apparatus includes, for example, a unitary, logical data storage area that is configured to store, using a common format, multiple types of data that are generated by or related to the process control system, the process plant, and to one or more processes being controlled by the process plant. For example, the unitary, logical data storage area may store configuration data, continuous data, event data, plant data, data indicative of a user action, network management data, and data provided by or to systems external to the process control system or plant. At other process control nodes, data (e.g., big data) is time-stamped, cached and/or stored, and then may be streamed to the big data apparatus for consolidation and storage.
Other nodes of a big data process control network may include, for example, process control devices such as controllers, field devices, and/or I/O (Input/Output) cards connecting field devices to controllers. Additional examples of nodes which may be included in a process control big data network are routers, access points, gateways, adaptors, etc.
In some process plant that support big data, at least some of the big data is locally stored, managed, and/or historized, e.g., the big data is distributively stored, managed, and/or historized across multiple nodes of the big data process control network. For example, each distributed big data node may locally store respective configuration data, continuous data, event data, plant data, data indicative of a user action, network management data, and data provided by or to systems external to the process control system or plant.
Further, whether at the big data apparatus and/or at distributed big data nodes, the big data process control system provides services and/or data analyses to automatically or manually discover prescriptive and/or predictive knowledge, and to determine, based on the discovered knowledge, changes and/or additions to the process control system and to the set of services and/or analyses to optimize the process control system or plant.
Irrespective of whether or not a process control system includes or does not include support for big data, though, an important aspect of distributed control systems is the ability to distribute and connect devices and components throughout a plant, or even throughout various plants owned or operated by a single company or organizational entity. These devices and/or components may vary in functionality. For example, some of the devices and/or components may be directly involved in controlling a process (e.g., a controller, a field device, etc.), and/or some of the devices and/or components may be involved in setting up, managing, maintaining, and/or diagnosing at least portions of a plant (e.g., configuration devices, diagnostic devices, data collection and analysis devices, etc.). Further, some of the devices and/or components may include a user interface (e.g., an operator workstation, a mobile computing device, a piece of testing equipment, etc.). At least some of the devices and/or components may be essentially stationary, such as a controller, pump, or sensor. At least some of the devices and/or components may be mobile, such as a laptop computer, a tablet computing device, or portable diagnostic tool.
Security of devices and/or components associated with a process control system of process control plant is emerging as a key topic of concern. Devices and/or components that connect to process control networks (and, in particular, mobile devices and/or components that dynamically connect to and disconnect from process control networks) must be secured so as to mitigate potential theft of data and malicious attack. Failure to do so may result in loss of control of the process and its output. Further, use of unsecure devices and components during real-time operation of a process plant may result in breaches of private networks and data and, in some cases, the occurrence of catastrophic events such as explosions, fires, and/or loss of equipment and/or human life. Still further, devices and/or components may need to be secured or verified for use in a process control system to validate the devices and/or components for their respective designated and intended use, as well as to mitigate possible illegal re-use and/or malicious use of the devices and/or components.